Fuel Injector Caps for Combustor Flow Uniformity
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Solution Overview
Problem
Existing combustor systems face challenges in evenly supplying compressed working fluid to aft injectors, leading to variations in fuel-air ratios and reduced cooling efficiency due to uneven pressure and flow distribution around the combustion chamber.
Innovation Solution
A system with circumferentially arranged fuel injectors and separate caps defining volumes outside the combustion chamber or liner, diverting a portion of the working fluid to cool the chamber before injection, ensuring a more uniform flow and pressure distribution through the injectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If compressed working fluid is diverted through aft injectors to increase combustion gas temperature, then thermodynamic efficiency is improved, but pressure and flow distribution around the combustion chamber becomes uneven
Solution Approach 1:
The system segments the working fluid flow path by introducing separate caps for each fuel injector, creating individual flow control volumes. This segmentation allows independent optimization of flow distribution to each injector while maintaining overall system efficiency.
Solution Approach 2:
Separate caps are provided for each fuel injector to define individual volumes around different injectors. This local quality approach ensures that each injector receives optimized flow characteristics tailored to its specific position, correcting the uneven distribution caused by circumferential variations in compressor output.
2Temperature
If compressed working fluid is diverted through aft injectors, then combustion gas temperature increases, but fuel-air ratio varies considerably
Solution Approach 1:
By providing separate caps for each fuel injector, the system segments the fuel-air mixing process into individual controlled volumes. This ensures that each injector receives a consistent and properly proportioned fuel-air mixture, eliminating the considerable variation in fuel-air ratio that occurs with conventional distributed injection systems.
3Productivity
If compressed working fluid is diverted through aft injectors, then combustion efficiency improves, but cooling provided to the combustion chamber is reduced
Solution Approach 1:
The separate caps are positioned to allow compressed working fluid to cool the combustion chamber externally before the fluid is diverted through the injectors. This preliminary cooling action ensures that the chamber is adequately cooled prior to fuel injection, preventing heat loss while maintaining combustion efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces variations in working fluid pressure and flow, enhances fuel-air mixture uniformity, maintains cooling efficiency, and improves thermodynamic performance by stabilizing the fuel-air ratio and emissions in combustors.
Implementation Method 1
The compressed working fluid exiting the compressor is often directed or channeled around the outside of the combustion chamber to convectively remove heat from the combustion chamber before flowing through the fuel nozzles.
Data Source
AI summary
A system for supplying a working fluid to a combustor includes a fuel nozzle, a combustion chamber downstream from the fuel nozzle, and a plurality of fuel injectors circumferentially arranged around the combustion chamber. The plurality of fuel injectors provide fluid communication into the combustion chamber, and a separate cap for each fuel injector defines a separate volume around a different fuel injector outside of the combustion chamber.